1. Technical Field
The present invention relates to an ink composition and a recording apparatus.
2. Related Art
In the related art, a printing method using an ink jet recording system is performed by causing an droplet of an ink to fly and adhere to a recording medium such as paper. By an innovative advance of ink jet recording technology in recent years, an ink jet recording apparatus using the ink jet recording system has been used even for various recording mediums such as plastics. A technology has been developed in which core-shell type polymer particles capable of suppressing an increase in the viscosity of an ink while improving the fixability of the ink to a recording medium made of plastics are added as a binder resin.
For example, in JP-A-2013-204025, in order to improve the drying properties and storage stability of an ink, the minimum film formation temperature of a core-shell type polymer particle is defined. In addition, in Japanese Patent No. 3257391, in order to improve water resistance and discharge stability, the glass transition temperature (Tg) of a polymer particle is defined. Further, in JP-A-2012-201692, in order to improve abrasion resistance and stable dischargeability, the difference in glass transition temperature between a core portion and a shell portion of a polymer particle is defined within a range of 10° C. or less.
In this manner, in JP-A-2013-204025, Japanese Patent No. 3257391, and JP-A-2012-201692, in order to improve the characteristics of an ink such as discharge stability and abrasion resistance, the characteristics of at least one of the polymer particle, the core portion, and the shell portion are defined. However, all the polymer particles disclosed in JP-A-2013-204025, Japanese Patent No. 3257391, and JP-A-2012-201692 do not have a core-shell structure in which the core portion is present inside the shell portion and the intended characteristics may not be obtained. FIG. 4 is an image obtained by photographing a polymer particle of the related art. As shown in FIG. 4, a core-shell structure in which the shell portion covers the core portion is not stably formed in the polymer particle. When the core-shell structure is not stably formed, there is a possibility that the abrasion resistance and intermittent properties of the ink may not be improved by the polymer particle.